This application claims the priority of German patent document 199 44 948.1, filed Sep. 20, 1999, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to a protective device for the interior of a motor vehicle having a protective structure, which can be spread out in a protective position to an at least approximately planar shape and which is seated for being transferred by a drive mechanism between at least two positions, the protective structure being connected with at least one guide element that can be entrained with transfer means of the drive mechanism by at least one coupling member.
A protective device according to the invention may be designed either as a horizontally movable cargo area covering, or as a separating device with a vertically extensible divider net, or as a roller blind for use as a sun shield for at least one window of a motor vehicle.
A protective device in the form of a cargo area covering has been known from German Patent Document DE 198 25 353 A1. The known cargo area covering comprises a horizontally extensible roller blind that can be moved, by electric drive means, between a home position in which the cargo area is exposed and a protective position in which the cargo area is covered. The covering roller blind comprises at its front endxe2x80x94viewed in the pull-out directionxe2x80x94a pull-out bar whose opposite ends project laterally beyond the roller blind that serves as the protective structure. These ends form guide elements that are respectively retained in a U-shaped upwardly open coupling member. Each coupling member is fixed to a toothed belt, serving as a transfer element, that extends in the pull-out direction, i.e. in horizontal alignment. Each toothed belt can be operated by means of an electric drive motor. The two drive motors can be controlled in a mutually co-ordinated way so that the pull-out bar and, thus, the covering roller blind can be pulled out or retracted in parallel. The ends of the pull-out bar that serve as guide elements can be removed from the coupling member in upward direction. Similarly, the pull-out bar can be reinserted between the coupling members from the top, whereby the covering roller blind can be connected again with the drive means.
If the pull-out bar were to hit against an obstruction when being pulled out or being retracted by the drive means, then the drive means and/or the pull-out bar may be damaged. In order to prevent any such occurrence there would be the possibilityxe2x80x94not disclosed in German Patent Document DE 198 25 353 A1xe2x80x94to monitor the load of the drive motors and to cause the direction of the drive to be reversed if an increase in load should be detected. Such devices are generally known in connection with the automatic opera-ion of vehicle window panes.
Now, it is an object of the present invention to provide a protective device of the kind described above that guarantees, by simple means, perfect and safe movement of the protective structure even in the case of trouble.
This object is achieved by the fact that at least one coupling member is provided with at least one picking-up element that has a limited retaining force for the force-dependent picking-up, entraining and release of the guide element during movement of the coupling member. Depending on whether the counter-force, that acts on the protective structure and the at least one guide element, is greater or smaller than the limited entraining force of the at least one picking-up element, the guide element is picked up from a stationary position, released from a position in which it has been entrained by the coupling member orxe2x80x94in the case of forces smaller than the retaining forcexe2x80x94entrained by the coupling member for common movement.
The solution according to the invention is suited for both, protective structures with only a single guide element and for protective structures having two or more guide elements. Depending on the particular configuration, a single coupling member or a plurality of coupling members may be provided. The drive means may have a single drive unit or a plurality of drive units. The drive unit comprises preferably a single central electric drive that imparts, by suitable synchronisation, a parallel guiding effect to the protective structure via two guide elements arranged on opposite sides. The solution according to the invention guarantees that the respective protective structure, be it a divider net, a covering roller blind of a cargo area covering, or a sun-protection roller blind, can be automatically transferred by the drive means into the desired position. Since when a load higher than that of the drive means occurs the at least one guide element and, thus, the protective structure will be uncoupled from the drive means, no overloading of the drive means can occur.
Due to the force-dependent coupling or uncoupling the at least one guide element will be released from the coupling member automatically and forcedly in the event the protective structure should hit upon an obstruction, while the coupling member will be moved on by the drive means. When the coupling member overruns the position of the guide element the next timexe2x80x94preferably in the opposite directionxe2x80x94the guide element will be automatically picked up again and carried off with the movement of the coupling member.
Uncoupling can be achieved in a simple way by the fact that the protective structure is moved manually in the direction of movement or in a direction opposite to the direction of movement of the drive means, whereby the protective structure is uncoupled. Thus, the coupling member has only a limited coupling force in the respective direction of movement of the at least one coupling member, through its at least one picking-up element. When this coupling force (entraining force) is exceeded, the protective structure is released from the at least one coupling member. Similarly, the guide element and, thus, the protective structure is connected again with the at least one coupling member as soon as the coupling member reaches once more the position of the guide element in the course of the corresponding reverse movement. It is, therefore, important that the guide element be always guided in the path of movement of the coupling member. The guide element remains in this path of movement even after it has been uncoupled, so that when the coupling member and the guide element meet the next time they are coupled once more. Thus, by overloading the coupling beyond the limited entraining force, i.e. coupling force, the at least one guide element and, thus, the protective structure will be detached form the drive means. Consequently, in case of a current failure, this also allows easy operation by hand without there being any needxe2x80x94as is the case with systems of the prior artxe2x80x94for manually re-engaging the at least one guide element in the coupling member later. Picking up of the at least one guide element and, thus, of the protective structure by the at least one coupling member is always effected automatically and, thus, forcedly in the solution according to the invention. The invention thus provides considerably improved operating comfort as compared to the prior art.
Overloading by obstructions found in the path of the protective structure is avoided. The at least one coupling member may be seated in horizontal or in vertical vehicle-mounted guides or in similar guides that are inclined in space. The guides may be parallel or non-parallel one relative to the other. In the case of non-parallel guides, length-compensation means are provided for the guide elements and the protective structure between the guides. The at least one coupling member is in any case forcedly guided in the same way as the at least one guide element of the protective structure in order to be able, as a result of the identical path of movement, to pick up the respective guide element every time it meets it.
In order to achieve a limited entraining force for the at least one picking-up element, the picking-up element may me movable in mechanically spring-loaded fashion. It is however also contemplated according to certain embodiments to provide the picking-up element and the guide element of the protective structure with corresponding magnetic elements. Embodiments with other force-locking or shape-locking connections with corresponding force limitation are also contemplated by the invention.
According to certain embodiments of the invention each coupling member is seated for linear movement in a vehicle-mounted guide section to which the corresponding guide element is also associated. This guarantees that the coupling member will S find the guide section again, after it has been transitorily separated from the coupling member, as soon as it passes once more the position of the guide element.
According to a further development of certain referred embodiments of the invention, the at least one picking-up element of the coupling member is mechanically active and seated to move transversely to the direction of movement of the coupling member, against the force of a return spring, between a holding position and releasing position. Consequently, the at least one picking-up element forms a force-dependent locking element of simple and safe structure, due to the mechanical function.
According to a further development of certain preferred embodiments of the invention, two coupling members, each entraining, releasing or picking up a guide element of the protective structure, are arranged on opposite sides for synchronous linear movement. Those embodiments are particularly well suited for use of the protective device as cargo area covering, where the opposite ends of a pull-out section, which serves as guide element, are each laterally held at limited force in corresponding coupling members that are guided for linear movement.
According to a further development of certain preferred embodiments of the invention, each coupling member has two picking-up elements which are adjusted to opposite directions of movement of the coupling member. The two picking-up elements preferably accommodate the respective guide element between them.
According to a further development of certain preferred embodiments of the invention, the one picking-up element is stronger, with respect to its entraining force, than the other picking-up element. This is of advantage when a tensile or pressure force is exerted upon the protective structure in the direction of movement, independent of the drive means. This is the case, in particular, with cargo area coverings in which the covering roller blind is held on a roller blind shaft that is loaded by a return spring. If the covering is then pulled out by hand, this guarantees that the covering roller blind will return to its home position immediately after unlocking. The described configuration is provided in order to prevent the respective tensile force or pressure force from being added to the drive force of the drive means and from thereby causing the at least one guide element to get detached from the picking-up element.
According to a further development of certain preferred embodiments of the invention, at least one stationary stop, serving to secure the protective structure in different positions, is associated to the at least one guide element, which stop can be transferred, by means of the at least one coupling member, into a releasing position in which it permits the protective structure to move. Consequently, such stationary movable stops are also found in the path of movement of the at least one coupling member so that when the stops are overrun by the at least one coupling member they will be forcedly transferred into the releasing position. This guarantees that the protective structure will be retained in the respective position by the stop so long as it is not picked up by the coupling member.
According to a further development of certain preferred embodiments of the invention, the stops are configured as spring-loaded, elastically resilient blocking elements provided with ramps for the respective coupling member. One thereby achieves simple releasing of the stops as soon as the coupling member passes the corresponding position of the respective stop. Preferably, corresponding stops are provided at least for the two end positions of the protective structure, i.e. a home position and a fully pulled-out protective position. Basically, however, it is also possible to provide only a single stop for the pulled-out protective position if the protective structure is held in the home position by a corresponding return spring.